The invention relates to a tomographic x-ray apparatus for the production of transverse layer images of a radiography subject, comprising a patient support, an x-ray measuring arrangement with an x-ray source supplied by an x-ray generator, which x-ray source generates an x-ray beam penetrating the radiography subject, and with a radiation receiver which determines the radiation intensity behind the subject, a drive device for the measuring arrangement with a rotating frame for generating rotational movements of the measuring arrangement, and a measurand converter for the transformation of the signals delivered by the radiation receiver into a layer image, wherein the current supply for the x-ray tube proceeds via a slip ring arrangement with sliding contacts which is arranged between the rotating frame and the stationary apparatus part.
A tomographic x-ray apparatus of this type is described, for example, in the German OS No. 27 16 818. It is designated as a computer tomograph and permits, due to the utilization of the slip rings, a permanent rotation of the measuring arrangement, and hence a very rapid scanning of the radiography subject from different directions. From the output signals of the radiation receiver formed at different projections, the measurand converter computes the attenuation coefficients of predetermined points of the examined transverse layer. The computed attenuation coefficient can be displayed in the form of a layer image on a television display unit.
In the case of the known computer tomograph, there are positioned on one shaft, several support members for the slip rings against which the sliding contacts are engaged in the radial direction. The slip rings and the sliding contacts are arranged in a receptacle filled with insulating oil. The utilization of insulating oil, however, signifies a relatively great outlay, in particular, also because this oil must be changed from time to time. In addition, in the case of the known computer tomograph, the possibility of movement of the radiography subject in the longitudinal direction of the support is restricted, since the slip ring arrangement with the sliding contact is provided at the one end of the computer tomograph and restricts the insertion path at that location.